Q Hello, I'm very interested in the new '07 Acura RDX sport crossover. With its turbocharged 240hp, 260 lb-ft of torque, all-wheel-drive automatic sport transmission, the vehicle has a lot of potential right from the manufacturer. And it's really exciting, being Honda/Acura's first venture into turbocharging a volume production car. But just like Tim Allen, I'm in search of more power. It would seem this car, being turbocharged, wouldn't be too difficult to modify for more power. Even a modest improvement of 25 additional horsepower or lb-ft of torque would make the driving experience even better. So I'd think that improving the air intake, exhaust and boost controller, or even a revised computer, might make for easy bolt-ons that would give the most bang for the buck. However, I've already looked at the websites for Hondata, Comptech and GReddy and didn't see any mention of the RDX at all. Do you know of any companies looking to produce performance aftermarket parts for the RDX or is the RDX one of those cars that will never get the research and development to go any further down the road to horsepower nirvana?
Thank you,
avid Turbo reader,
Ted Varamogiannis,
Albany, N.Y.
A Ted, unfortunately, I don't have much good news for you. For now. There are a few problems with the RDX. First, it features drive-by-wire throttle, which means companies like Hondata really have their hands tied as far as ECU modifications go. They've yet to develop a truly tunable solution for the '06 Si, which has been out significantly longer and, frankly, is a lot more popular with enthusiasts than the RDX ever will be. There's no reason why these computers can't be reprogrammed or reflashed though, but only time will tell whether or not it's worth it for companies like Hondata to offer this. Our guess is they will. As far as intake and exhaust components go, it's likely we'll be seeing these in the near future but, given the car's SUV sort of status, we're not expecting an abundance of such parts. Do a quick search on eBay though and you'll see a few entry-level intakes already out there. On a good note, it appears as though Eibach has taken the lead and already has some suspension components out for the RDX. Hopefully other top-notch companies will follow. As far as turning up the boost, this could be more complicated than simply splicing in a boost controller. The RDX's turbo boost is regulated not just by a wastegate but also by a pair of solenoids and a variable flow control valve, all managed by that pesky ECU. The good news is that the engine itself is similar to the TSX's. That means camshafts and valvetrain components can be shared with those of the RSX Type S - a good thing - and engine block components are readily available. The hardest part will be finding external bolt-ons specifically made for the RDX.
Q I work at Bommarito Mazda in St. Peters, Mo. and own a 2003 and a half Mazdaspeed Protg. I've talked to many technicians here and they tell me if you mess with the wastegate to get more boost, you'll mess up the pistons and rods. I was reading your Mazdaspeed Protg article where you put in the AVC-R boost controller and turned the boost up to almost 15 psi. Can a factory car run safely on that much boost or will it hurt the internals? How long do you think it will safely run if it can?
Thanks guys,
love the mag,
Nick Vito
A Nick, you probably know this, but the wastegate has nothing to do with your pistons and rods. The fact is, if you turn up the boost by any means you risk damaging the engine. But it's all relative; 15 psi on your Protg creates a different amount of cylinder pressure than 15 psi on, say, a Garrett GT42 turbo. Depending upon octane and driving characteristics, 15 psi on that particular turbo is doable. The problem is that the ECU's fuel and ignition maps are already tuned for whatever the preset boost level is. Also, keep in mind, we upgraded our Protg with a front-mount intercooler and a free flowing exhaust. This helps reduce intake temps as well as exhaust gas temps - both good things to take into account when turning up the boost. I'd recommend getting yourself a wideband air/fuel ratio meter, that way you can keep an eye on what's going on as you turn up the boost. Turn it up cautiously, a few pounds at a time, and keep an eye on those air/fuel ratios - those are what'll ultimately put holes in those pistons and bend those rods.
Q I've been reading Turbo for almost as long as I've had my '89 CRX, 10 years now. Over the years I've done a B17A1 swap (before engine mount kits were so readily available) and fabricated two custom turbo setups myself. I usually spend more time under the hood installing parts I've made than behind the steering wheel, but I enjoy working on it and giving it a personal touch just as much as I do driving it. I've come to the point where I want to rebuild the car into something different from everything else out there. This is where you come in. I'd like to convert the car to rear-wheel drive. I've seen it done on a couple of front-wheel-drive Hondas but in most cases the engine is relocated to the rear wheels. I think it would be more impressive to keep the engine up front and to turn it 90 degrees. I'd like to keep my B17A1 since it was the first engine built for the 1993 model-year Integra GSR (serial # 00001), which is something I'm proud to own. What transmission can I find that spins counterclockwise to mate to my engine. I'm not concerned about making an adapter, I'd be comfortable handling that with my 10-year background as a tool and die maker. I considered using a regular clockwise-turning transmission and just flipping the rear end that goes with it, but then the tranny would be spinning backwards and this would be unreliable unless the transmission has straight cut gears. I have yet to find one that will work for my application. My only other options are to have a custom transmission built (which will burst my budget), or to break down and do a complete drivetrain swap from a different car altogether, but I'd love to keep my B17. Any help is greatly appreciated.
Regards,
Aaron Weir
A You forgot you're other option: just buy a rear-wheel-drive car to begin with. Sorry, I had to say it. OK, first with the disclaimer: We wouldn't recommend converting a FWD Honda to RWD. It will never handle like a RWD car should, and it WILL cost you more than just shelling out for a used MR2, Miata or 240SX in the first place. Even used S2000's aren't all that expensive nowadays; but you didn't ask our opinion, did you? Sorry again. I won't mention the time involved either because I get the impression you'd be OK with any time frame, no matter the length. Now, with that out of the way, I'd still like to help you. There's a reason most RWD Honda conversions stick the engine in the trunk; it's the easiest and most reliable way you could get this done. This will allow you to use whatever FWD gearbox you already have and keep your counterclockwise-spinning B17A, of course, with some fabrication. You'll need to make your own subframe of sorts for the rear and you'll also need to gather the appropriate uprights, hubs and correct length axles - all custom. Of course, you'll also need to address the cooling system, fuel system and wiring harness, but all of these things can be relocated, altered or lengthened. But you don't want to put the engine out back. Understandable. But it's going to be difficult. There's not a lot of room for a driveshaft under there and chassis support out back for a rear end is scarce. Honda's also about the only company that spins their engines counterclockwise with the exception of the one transmission you might have first assumed you'd be able to use - the S2000's. Oh wait, scratch that, I'm pretty sure Chevy Corvairs spin backwards too.
Q Hey Aaron, I saw a set of wheels for both the 510 and 240Z featured in your magazine. The write up said they were DAZZ Wheels. I went to their site and found nothing for these applications. I have both a 1972 510 and a 240Z, and I can't find newer wheels for cars that old with the four-bolt pattern. Can you assist me in my search?
Thanks,
Brian
A Brian, those Chevlon Racing wheels are pretty hard to get. I believe DAZZ special orders them from Japan. I'd check out their website or call them direct and see if somebody over there can help you out (www.dazzmotorsports.com). You probably won't find wheels specifically offered for your car though, but if you know your bolt pattern and what kinds of clearances you have to work with (like suspension components, rotors, calipers and fenders) you should be able to find more than a few newer wheels that will fit.
Correction
In your July '07 issue you have a mistake in the 850whp 300ZX article. You claimed Steve Millen piloted a 300ZX to over 260mph when in fact he didn't; that was S. Koyama driving the JUN-Blitz 300ZX at the Bonneville Salt Flats. This isn't to downplay Steve Millen's accomplishments, as he remains to this day the most-winning driver in IMSA GTS history.